Apache Web server notes
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Apache Web server notes

The Apache Web server has the following notes:

• Tasks to perform before you use the Apache Web server agent
• About detecting application failure
• About bringing an Apache Web server online outside of VCS control
• About high Availability fire drill

Tasks to perform before you use the Apache Web server agent

Before you use this agent, perform the following tasks:

• Install the Apache server on shared or local disks.
• Ensure that you are able to start the Apache Web server outside of VCS control, with the specified parameters in the Apache configuration file
  (for example: /etc/apache/httpd.conf). For more information on how to start the server:

  See About bringing an Apache Web server online outside of VCS control

• Specify the location of the error log file in the Apache configuration file for your convenience (for example: ErrorLog /var/apache/logs/error_log).
• Verify that the floating IP has the same subnet as the cluster systems.
• If you use a port other than the default 80, assign an exclusive port for the Apache server.
• Verify that the Apache server configuration files are identical on all cluster systems.
• Verify that the Apache server does not autostart on system startup.
• Verify that Inetd does not invoke the Apache server.
• Remove previous versions of this agent.
• The service group has disk and network resources to support the Apache server resource.
• Assign virtual host name and port to Apache Server.

About detecting application failure

The agent provides two methods to evaluate the state of an Apache HTTP server instance. The first state check is mandatory and the second is optional.

The first check determines the state of the Apache HTTP server. The check determines the state by searching for the existence of the parent httpd daemon. It also searches for at least one child httpd daemon. If the parent process and at least one child do not exist, VCS reports the resource as offline. If they do exist, and if the agent attribute SecondLevelMonitor is set to true, then a socket connection is established with the Apache HTTP server using the values specified by the Host and Port agent attributes. When connected, the agent issues an HTTP request to the server to test its ability to respond. If the HTTP Server responds with a return code between 0 and 408, the agent considers the server online. If the server fails to respond or returns any other code, the agent considers the server offline.

About bringing an Apache Web server online outside of VCS control

When you bring an Apache Web server online outside of VCS control, first source its environment file. Start the server with the -f option so the server knows which instance to start. You can then specify additional options (such as EnableSSL or SharedObjDir) that you want the server to use at start.

To start an Apache Web server outside of VCS control

1. Source the environment file if required.
2. Start the Apache Web server. You must use the -f option so that the agent can distinguish different instances of the server.

   httpdDir/httpd -f ConfigFile -k start

   Where httpdDir is /apache/v2.2/bin ConfigFile is /apache/v2.2/conf/httpd.conf. When fully formed, the start example looks like:

   /apache/v2.2/bin/httpd -f /apache/v2.2/conf/httpd.conf -k start

3. Specify additional options such as EnableSSL or SharedObjDir that you want to use when you start server. When you add EnableSSL to the command, it resembles:

   httpdDir/httpd -f ConfigFile -k start -DSSL

About high Availability fire drill

The high availability fire drill detects discrepancies between the VCS configuration and the underlying infrastructure on a node. These discrepancies might prevent a service group from going online on a specific node. For Apache resources, when the Apache Web server is installed locally, the high availability fire drill checks for the validity of these attributes:

• ConfigFile
• httpdDir

For more information about using the high availability fire drill see the Veritas Cluster Server Administrator's Guide.